I have to agree with BlackBerry Guy. I was in a similar position to you -- though I had an old Air and I needed more storage, as well as it starting to bog down at times. I just couldn't justify the extra price on the iPad Pro. I won't use the Pen or the Keyboard -- and I have a Bluetooth Keyboard that works great with the iPad, if I want it. While the stereo sound is a nice feature on the Pro, I rarely listen to music from the iPad speakers; I typically listen to music through headphones or will use a Bluetooth speaker, and the Pro speakers don't compare to external speakers. Last, while I've had to limit what I put on my iPad because I've been out of storage, 128 GB is plenty of storage, I don't need the 256 GB you can get on the Pro.
I've bought the new iPad and am very happy with it. It has been a nice upgrade from my Air, it feels much faster and I've had no issues. Since the Air also didn't have the laminated screen or anti-reflective coating, I don't miss not having it and the screen still looks very good. Also, I'm likely going to add a screen protector that will add the anti-reflective coating.